Tuesday will offer up the final round of security bulletins for 2012. December's Patch Tuesday will include seven security bulletins: five critical and two important. The bulletins address 12 vulnerabilities.

"The critical bulletins address vulnerabilities in Microsoft Windows, Word, Windows Server and Internet Explorer," said Dustin Childs, group manager for Microsoft Trustworthy Computing. "The two Important-rated bulletins will address issues in Microsoft Windows."

Childs recommended customers pause from searching for those hot new gadgets and review Microsoft's ANS summary page for more information on the coming patches. He also asked IT admins to prepare for bulletin testing and deployment as soon as possible to help ensure a smooth update process.

A Mix of Vulnerabilities

Wolfgang Kandek, CTO of Qualys, told us all in all, IT admins are looking at a normal-size Patch Tuesday with a mix of browser, operating system and Office updates that will keep all areas of IT administration busy through the end of 2012.

"For many Windows RT users, it will be the first time for a software update, and it will be interesting to see how they react and what the uptake of the patches will be," Kandek said as he offered his analysis of each bulletin.

Bulletin 1 is rated critical and affects Internet Explorer 9 and 10 on all platforms that support IE 9 and IE10, starting at Vista all the way to Windows 8 and RT. Bulletin 2, which is also rated critical, applies to all versions of Windows and again includes both Windows 8 and Windows RT.

A Rare Bug

"Bulletin 3 is special, as it affects Microsoft Word and is rated critical, which happens very rarely. Usually Microsoft downgrades even Remote Code Execution Office vulnerabilities to 'important,' because a user interaction, such as opening a malicious file, is required," Kandek said.

"In this case we assume the 'critical' rating comes from Outlook, which can be configured to use Word to visualize documents in its preview pane. This is an automatic mechanism that does not require user interaction. In any case, this will be an important bulletin to watch out for."

Bulletin 4 is a critical fix for a number of Microsoft server software products. Kandek said it includes the widely installed Exchange and SharePoint, plus an update for Microsoft Office Web Apps 2010 Service Pack 1.

"Office Web Apps are the webified version of Word, Excel, etc., and we expect them to have lesser impact on IT, as the applications have fewer installations," he said. "In any case, Server Administrators need to take a good look at this bulletin to see if they need to take action."

Web-Based Attack Risks

Marcus Carey, a security researcher at Rapid 7, told us Bulletins 2 and 5, both critical, will affect most consumers and enterprises since they fix vulnerabilities that would allow an attacker to remotely execute code on all Windows platforms. Both of these bulletins fix vulnerabilities that potentially could be leveraged as web-based attacks, he said, however they would be difficult to exploit and achieve remote code execution.

"Bulletin 6 is rated as important and affects all supported Microsoft operating systems except for Windows RT. Since it's rated as important it probably requires a special set of circumstances to actually exploit, which would probably require some sort of victim participation such as opening malicious files," Carey said.

"Bulletin 7 is important and only affects Windows Server 2012 and Windows Server 2008 R2. It could allow an attacker to bypass at least one security measure on those operating systems. Since it is rated as important it may only work under limited circumstances and configurations."